[Geomoose-users] Performance issues

[Brent Fraser]

Jeff,

  I only started to look into WMS tiling, so I'm guessing.  I expect that
OpenLayers is requesting multiple images (tiles) from mapserver instead
of just one [larger] image.  If you had some sort of file caching
enabled on the server, you would see a performance improvement
(especially if your mapserver map files had only one or two layers), as
the file server would return the previously rendered image instead of
asking mapserver to [re]generate it.  Have a look at tilecache.org?

Brent

> Thanks for the responses!
>
> We were using WMS for two reasons: we wanted to make our data easily
> accessible, and we wanted to take advantage of tiling so that users
> could move the map around without the need for it to refresh
> continually. This week, we tried disabling the tiling, and performance
> improved significantly, to be just about as quick as using them as map
> server layers. Any idea why tiling would create such a drastic
> decrease in performance?
>
> Also, our mapbook is rather large (we have quite a few layers), so I
> included a snippet of what a typical map source entry looks like when
> we use WMS with tiling:
>
> <map-source name="hashed_layers" type="wms" tiled="true"
> queryable="false" projection="EPSG:900913">
>                <url>http://maps.glifwc.org/development/glifwc_wms.php</url>
>                        <layer name="mn_bathymetric_contours"/>
>                        <layer name="cooperative_weed_management_areas"/>
>                        <layer name="eab_quarantine_counties"/>
>                        <layer name="minor_watersheds"/>
>                        <layer name="major_watersheds"/>
>                        <layer name="great_lakes_watersheds"/>
>                <param name="format" value="image/png" />
>                <param name="TRANSPARENT" value="TRUE" />
>        </map-source>
>
> Thanks again for the help!
> -Jeff
>
> On Tue, Jul 27, 2010 at 9:29 AM, Brent Fraser <bfraser at geoanalytic.com>
> wrote:
>>  Are you using the same map file for both WMS and Mapserver CGI?
>>
>>  While I've used mapserver as a WMS server to produce a single image per
>> request, I've never used it to produce WMS tiles.  Can you give more
>> details
>> on your config?  What does your mapbook map-source entry look like?
>>  What
>> does the WMS CGI request(s) look like?
>>
>> Best Regards,
>> Brent Fraser
>>
>> Jeffrey Schmitz wrote:
>>>
>>> Hey guys, I am having performance issues, and was wondering if anyone
>>> had any tips on how we could possibly speed up our site. Our current
>>> setup:
>>>
>>> We have a postGIS table with data in WGS84(EPSG:4326). It is defined
>>> such in our mapfile layer definitions, and projected by mapserver as
>>> Web Mercator (EPSG:900913) for web map services, which are served by
>>> geomoose.
>>> Currently, with only a couple of layers turned on (Wisconsin,
>>> Minnesota and Michigan counties, and the great lakes), our site takes
>>> a LONG time to load (45seconds to a minute). It appears to me that
>>> this is an issue with our setup, not network speed. If launched in
>>> firefox, you can see that the page loads fine, but is slow when
>>> loading the wms tiles (you see "waiting" for a while and then
>>> "transferring"  for a couple seconds, and then "waiting" again for
>>> long periods).
>>>
>>> We also have an identical site that uses mapserver and mapfiles
>>> directly instead of WMS, and it loads in everything in just a couple
>>> of seconds.
>>>
>>> Does anyone have any suggestions as to why we would be seeing such
>>> significant slow down when using web map services?
>>>
>>> Thanks for any help!
>>>
>>> Jeff